The present invention relates to a cutting tool and in particular to a tool for cutting an annular groove on the interior of a substantially cylindrical surface.
While this invention is suitable for cutting an annular groove on the interior of any substantially cylindrical surface, it will be discussed herein in particular in relationship to cutting an annular groove in the acetabulum of a body for preparation of the acetabulum socket to receive an acetabulum cup during hip replacement surgery. One of the greater problems of cement fixation of cup arthroplasty has been getting good fixation at the cement/bone interface. Several efforts have been made to improve this cement/bone interface. One method has used plastic spacers between the bony acetabulum and the plastic cup to allow an acceptable amount of cement to rest between the acetabulum and the cup. Other procedures have used surgically placed drill holes in the bony acetabulum and then the acetabulum and the drill holes are filled with cement of a doughy consistency. An acetabular cup is then inserted into the acetabulum and manual pressure is applied to the cup to force the cement between the trabeculae of the bone and into the drill holes. Other procedures utilize an acetabular cup having large screw threads on the outer periphery and the cup is actually threaded into the cup shaped acetabulum.
As described in copending patent application Ser. No. 748,856 filed June 26, 1985 and entitled Method and Apparatus for Cementing an Acetabular Cup to an Acetabulum, it was pointed out that after the acetabulum is prepared by using a first size reamer to remove the cartilage from the deepest portion of the acetabulum to form a spherical area in the weight bearing portion of the acetabulum and, where possible, by using a second, larger diameter reamer to remove the cartilage from the shallow portion of the acetabulum to form a second, larger spherical zone, that at least one annular groove can be formed at least in the spherical zone of the acetabulum about the inner periphery thereof to provide added fixation of the cement to the bone. Other annular grooves can be formed in the spherical zone and/or the spherical area of the acetabulum.
Thus, it is an object of the present invention to provide a tool for cutting an annular groove on the interior of a substantially cylindrical surface such as the spherical area or spherical zone of an acetabulum for receiving cement for enabling better cement/bone fixation.
It is another object of the present invention to provide a tool for cutting an annular groove on the interior of an acetabulum of predetermined depth.
It is still another object of the present invention to provide a tool for cutting annular grooves on the interior of the acetabulum at different diameters or elevations of the acetabulum.